| 年份 | 尼日尔 |
|---|---|
| 2023 | - |
| 2022 | 0.162615 |
| 2021 | 0.164707 |
| 2020 | 0.167476 |
| 2019 | 0.167653 |
| 2018 | 0.165059 |
| 2017 | 0.162868 |
| 2016 | 0.160654 |
| 2015 | 0.157996 |
| 2014 | 0.155431 |
| 2013 | 0.153228 |
| 2012 | 0.150622 |
| 2011 | 0.148008 |
| 2010 | 0.146132 |
| 2009 | 0.144557 |
| 2008 | 0.143367 |
| 2007 | 0.142481 |
| 2006 | 0.141682 |
| 2005 | 0.140792 |
| 2004 | 0.139802 |
| 2003 | 0.138651 |
| 2002 | 0.137327 |
| 2001 | 0.135917 |
| 2000 | 0.13431 |
| 1999 | 0.132581 |
| 1998 | 0.13067 |
| 1997 | 0.128661 |
| 1996 | 0.126674 |
| 1995 | 0.123856 |
| 1994 | 0.120354 |
| 1993 | 0.116856 |
| 1992 | 0.113358 |
| 1991 | 0.10971 |
| 1990 | 0.105649 |
| 1989 | 0.101336 |
| 1988 | 0.0968309 |
| 1987 | 0.0922674 |
| 1986 | 0.0876387 |
| 1985 | 0.0828118 |
| 1984 | 0.0778726 |
| 1983 | 0.0725743 |
| 1982 | 0.0670505 |
| 1981 | 0.0618466 |
| 1980 | 0.0572407 |
| 1979 | 0.0532517 |
| 1978 | 0.05017 |
| 1977 | 0.0481592 |
| 1976 | 0.0465295 |
| 1975 | 0.0447356 |
| 1974 | 0.0427024 |
| 1973 | 0.0402836 |
| 1972 | 0.0373383 |
| 1971 | 0.0343422 |
| 1970 | 0.0318598 |
| 1969 | 0.029949 |
| 1968 | 0.028846 |
| 1967 | 0.0285594 |
| 1966 | 0.0285401 |
| 1965 | 0.0285243 |
| 1964 | 0.0283824 |
| 1963 | 0.027966 |
| 1962 | 0.0273305 |
| 1961 | 0.027037 |
| 1960 | 0.0277245 |